Needlestick injuries frequently occur among healthcare workers, introducing high risk of blood-borne pathogen infection for surgeons, assistants, and nurses, such as HIV, hepatitis B, hepatitis C or viral hemorrhagic fevers. In a UK report, 37% of nurses reported that they have sustained a needle-stick injury at some stage during their career (Prevention CfDCa, Overview: Risks and Prevention of Sharps Injuries in Healthcare Personnel, CDC, Atlanta, Ga., USA, 2004). These results have further to be read taking into account that not all needle-stick injuries are reported, and that the rate of detection may be low. In a study investigating the use of blunt needles during obstetrical laceration repair surgeries (Wilson et al., “The use of blunt needles does not reduce glove perforations during obstetrical laceration repair”, Am J Obstet Gynecol., 2008, 199(6):641.e1-3), only 11% of glove perforations were detected by the physician in a study.
Strategies are available in response to these issues, including education of healthcare workers on the risks and precautions, reduction of invasive procedures, management of exposures and use of safer devices.
Among the safest devices, an efficient way to protect a healthcare worker from being pricked by a needle is the use of safety syringes. Such syringes have the particularity to comprise a sheath protecting the needle, which can be retracted or extended. In a retracted position, the needle is completely covered and secured by the sheath. In an extended position, the needle projects outside the sheath.
A major issue when designing such safety syringes, further to securing the needle, is the ease of use of said safety syringes. Even though the protection sheath may enhance safety, its volume may make the syringe uneasy and cumbersome to manipulate.
Several safety syringes comprising a sheath have been proposed in the literature. However, none of them describes a sheath according to the invention, designed for an improved convenience and an improved safety for the healthcare worker.
For example, International Patent application WO 2006/105006 discloses a safety syringe including locking positions, formed by an inner sleeve receiving a cartridge filled with liquid, an outer sleeve through which said inner sleeve is telescopically reciprocated, and a plunger assembly that is attached to the inner sleeve and used to eject the liquid. This device is capable of both intermittent locking during use RU as well as permanent locking after use RAU (page 5, lines 2-3), performed by pushing inward a tab which engages permanently a hole. However, there is no specific retracted position before use RBU.
US patent 2011/0082428 relates to a safety structure for covering a syringe needle including a safety sleeve and a hub. The safety sleeve is fitted around the hub and provided with an axial sliding slot, a locating slot laterally extended from the sliding slot and a locating hole located at a bottom of the locating slot. The protective sheath comprises a “retracted position before use” in the locating slot, an “ejection position” in the sliding slot and a “retracted position after use” in the locating hole. However, this device does not provide a “retracted position during use”. Moreover, this safety structure does not provide a one-way path for the male means of the hub through the female means of the safety sleeve: backtracks are indeed needed in order to access to the various retracted positions (RBU, RU and RAU). Thus said safety structure lacks of convenience and safety.
U.S. Pat. No. 4,994,045 discloses a safety syringe including a conventional syringe, a locating ring and an elongated and tubular sheath. This device is capable of both intermittent and permanent positions where the needle is secured, allowing the user to extend or retract the tubular sheath at will during use (ejection position E and retracted position during use RU), and to definitely secure the needle after use (retracted position after use RAU). However, the various retracted positions are not transversally aligned (see FIG. 2 of U.S. Pat. No. 4,994,045), resulting in a non-optimized sheath length as described further in the description of the invention.
European Patent EP 1 603 612 discloses a preservative sheath for an injection needle or cannula arranged on a cannula-holding support which can be fitted onto a syringe. The sheath comprises guide means, which may be ramps, allowing the cannula to be in a retracted position before use RBU, a retracted position during use RU, a retracted position after use RAU and an ejection position E. However, the various retracted positions are not transversally aligned, resulting in a non-optimized sheath length as described further in the description of the invention. Moreover, the RU position comprises no temporary locking means.
U.S. Pat. No. 5,312,370 discloses a needle protecting device adapted for use on a standard syringe, especially a conventional dental syringe able to receive a cartridge. The sheath of this device may be rotated from an intermediate locked position during use RU to a final locked position after use RAU securing the needle. However, there is only one possible intermediate locked position (as described column 8 of U.S. Pat. No. 5,312,370). This device provides no specific retracted position before use RBU.
Therefore, there is still a need in the art for a needle protective sheath improving the healthcare worker's convenience and safety.